公开(公告)号：US3790845A

公开(公告)日：1974-02-05

申请号：US3790845D

申请日：1972-06-28

Applicant: RCA CORP

Inventor： CAMPBELL F

IPC: H01J29/07 ,  H01J29/80 ,  H01J29/81 ,  H01J31/20 ,  H04N9/18 ,  H01J29/70

CPC classification number: H01J31/201

Abstract: Voltage applied to the grill of a focus-grill, color cathode ray tube is modulated at vertical scanning frequency. When scanning along the top and bottom edge portions of the grill, potential applied to the intermediate portion of the grill is increased, thereby correcting for overfocus in the vicinity of the vertical axis by narrowing the width of the focused electron beam on the screen. This avoids color impurity at the top and bottom regions of the screen. When scanning along the region of the horizontal axis, potential applied to the intermediate portion of the grill is decreased, thereby correcting for underfocus in the vicinity of the vertical axis by narrowing the width of the focused beam and thus avoiding color impurity in that region. The voltage modulations are progressively proportioned or damped by resistor means in directions outwardly toward the left and right edge portions of the grill, to which constant potential is applied. Damping the applied voltage modulation to a constant potential avoids color impurity at the edge portions, which have very high color purity sensitivity to grill voltage change.

Abstract translation: 施加到焦点格栅的彩色阴极射线管的栅极的电压以垂直扫描频率被调制。 当沿着格栅的顶部和底部边缘部分扫描时，施加到格栅的中间部分的电位增加，从而通过使聚焦的电子束在屏幕上的宽度变窄来校正垂直轴附近的过度聚焦。 这避免了屏幕顶部和底部区域的杂质杂质。 当沿水平轴的区域扫描时，施加到格栅的中间部分的电位减小，从而通过缩小聚焦光束的宽度来校正垂直轴附近的欠焦点，从而避免该区域中的杂质。 电压调制通过电阻器装置逐渐成比例地或向着向格栅左右边缘部分的方向阻尼，施加恒定电位。 将施加的电压调制抑制到恒定电位可避免在边缘部分产生颜色杂质，这对于格栅电压变化具有非常高的色纯度灵敏度。